1. Field of the Invention
The present invention relates generally to dual damascene semiconductor manufacturing processes, and more particularly, to methods and systems for planarizing features and layers and controlling surface roughness in a semiconductor manufacturing process.
2. Description of the Related Art
Dual damascene manufacturing processes are becoming more common in semiconductor manufacturing. In a typical dual damascene manufacturing process, one or more conductive materials are deposited in previously patterned trenches and vias formed in a semiconductor substrate or films formed on the semiconductor substrate to form the desired electrical circuit interconnects. An excess or overburden portion of the conductive material is often formed. The overburden portion of the conductive material is unnecessary and undesirable and must be removed both to produce a damascene feature and to provide a uniform and planar surface for subsequent processing.
The overburden portion of the conductive material is typically removed from the semiconductor substrate through chemical mechanical polishing (CMP) and electro-chemical polishing (ECP) (e.g., etching) processes and combinations of CMP and ECP processes. Each of these processes has significant shortfalls. By way of example, ECP typically has a relatively low throughput, poor uniformity and inability to effectively remove non-conductive material.
CMP requires physical contact processes which typically leave conductive residues, or cause corrosion of the various materials, or result in non-uniform removal, and the inability to suitably planarize interconnect and interlevel dielectric (ILD) top surface. CMP can also cause stress related damage (e.g., interlayer delamination, peeling) to remaining interconnect and ILD structures. The CMP-caused stress damage is further exacerbated by the very poor inter-layer adhesion characteristics of the more-recently used materials. Reducing the physical force of the CMP process to reduce the physical stress can often result in unacceptably low throughput rates and other poor process performance parameters.
In view of the foregoing, there is a need for an improved system and method to remove at least a portion of a layer and to provide a substantially smooth surface while minimizing physical stress to the remaining features. The improved system and method should be suitable for use in semiconductor manufacturing and should be applicable to processes such as a dual damascene process or other semiconductor manufacturing processes.